The invention is directed to erosion control systems of the type in which a surface to be protected is covered with a layer of interlocking concrete blocks, usually laid on top of a filter mat or blanket which allows free passage of water but prevents erosion of underlying material. Sometimes the blocks in such systems are interconnected by wires passing through holes in the blocks, the wires usually being of stainless steel so as to resist corrosion.
It has been proposed, in order to facilitate laying of the blocks, particularly when the surface to be protected is partially below water during installation of the blocks, to preassemble the blocks into panels which are strung together using the wires which will connect the blocks, and bodily laid in place using a crane. The panels may either be preassembled on site, or assembled elsewhere and brought to the site on a truck or barge.
A problem using such a system is that the wires connecting the blocks need to be strong enough reliably to support the panels during the operations of hoisting the panel and laying it in position. Even assuming that during the hoisting operation, the wires are arranged to run vertically through the panel, the stresses on the wires will be considerable, and there is no guarantee that they will be evenly distributed over the different wires. This necessitates the use of considerably heavier wire to assemble the panels than is actually necessary to maintain the integrity of the panel once laid in position, and since the wire utilized is of stainless steel and expensive, the problem militates against the utilization of the system where alternatives are available. It also severely restricts the size of panel that can be handled if wires of reasonable gauge are to be utilized.
The present invention is directed towards overcoming this problem.